1. Field of the Invention.
The present invention relates to a capture collar placed on the neck of an animal that mounts darts for injection of drugs for immobilizing the animal in response to signals.
2. Prior Art
Radio tracking further studies of wildlife ecology by allowing investigators to find and identify individual animals at will. Radio tracking using transmitters attached to the animal has been done extensively in wild animal studies but difficulty is encountered in recapture. The result is a one-time examination of the study animal's nutritional and physiological condition followed by surveillance and a history of the creature's survival and behavioral and ecological interactions. Simultaneously blood sampling, hair sampling, and other physiological testing provide insight into the physiological state and nutritional condition of wild animals.
Radio-tracking and physiological testing are readily combined because to attach a radio-transmitter collar to an animal, the investigator must capture the creature and the researcher can then also conduct physiological tests.
However, because an animal's physiology and nutritional condition changes constantly, samples and tests taken only at initial capture, or at infrequent recaptures of study animals, provide an incomplete assessment of the animals condition. In addition, such procedures as the sodium-turnover technique for determining food consumption in carnivores and other procedures require that individuals be recapturable at certain preselected intervals. Thus a method is needed to recapture animals at will.
Mehods used to capture and recapture animals include live-traps, nets, rifles and pistols firing anesthetic darts, drug-laced food stuffs, etc. For the most part, these methods are unpredictable as to when an animal will be captured, and require proximity to the animal and intensive effort, or else constant monitoring. Furthermore, the methods now used are usually totally unreliable in taking any given animal at will.
One method used employed a radio-triggered drug capsule implanted in baboons carrying backpacks (R. L. Van Citters, O. A. Smith, D. L. Franklin, W. S. Kemper, and N. W. Watson, 1967, in The Baboon In Medical Research II, H. Vastbors, Ed., University of Texas Press, Austin pp. 473-492; R. L. Van Citters and D. L. Franklin, 1969, Radio Telemetry Techniques For Study Of Cardiovascular Dynamics In Ambulatory Primates, Annals N.Y. Acad. Sci. 162: 137-155). A needleless "syringe" was implanted subcutaneously on baboons with wire leads running from it to the electronic unit in the backpack. The "syringe" consisted of a stainless-steel cylinder with a small hole at one end stoppered by silicon rubber. A rubber piston was friction-fitted into the opposite end, and the chamber filed with a tranquilizing agent. A wad of nitrocellulose was placed behind the piston and secured by a model airplane engine glow-plug. When the device was triggered by remote radio transmission the hot glow-plug exploded the nitrocellulose, driving the piston forward, and injecting the tranquilizer subcutaneously.
Shortcomings of the backpack method are that it required an implanted "syringe" with transcutaneous leads to the triggering mechanism within the backpack. This type of design can lead to infection at the site of entrance of the wire leads through the skin, and breakage of the leads upon movement of the backpack. The leads are also subject to breakage and deliberate removal by associate animals. Furthermore, it requires a surgical operation, with attendant difficulties and potential complications, following each capture to remove the spent "syringe" and replacing it with a fresh "syringe". The backpack was not used to recapture individual animals repeatedly. Animals were recaptured primarily to remove the backpack since it contained expensive physiological measuring electronics.